Apparatus for performing an electrosurgical procedure

ABSTRACT

A forceps is provided and includes a housing having a shaft. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member from a clamping position to an open position. A resilient member operably couples to the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 12/792,330, filed Jun. 2, 2010, the content of which is incorporatedherein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an apparatus for performing anelectrosurgical procedure. More particularly, the present disclosurerelates to an electrosurgical apparatus including an end effectorassembly having a pair of jaw members that provide a mechanicaladvantage at the end effector.

2. Description of Related Art

Electrosurgical instruments, e.g., electrosurgical forceps (open orclosed type), are well known in the medical arts and typically include ahousing, a handle assembly, a shaft and an end effector assemblyattached to a distal end of the shaft. The end effector includes jawmembers configured to manipulate tissue (e.g., grasp and seal tissue).Typically, the electrosurgical forceps utilizes both mechanical clampingaction and electrical energy to effect hemostasis by heating the tissueand blood vessels to coagulate, cauterize, seal, cut, desiccate, and/orfulgurate tissue. Typically, one or more driving mechanisms, e.g., adrive assembly including a drive rod, is utilized to cooperate with oneor more components operatively associated with the end effector toimpart movement to one or both of the jaw members.

In certain instances, to facilitate moving the jaw members from an openposition for grasping tissue to a closed position for clamping tissue(or vice versa) such that a consistent, uniform tissue effect (e.g.,tissue seal) is achieved, one or more types of suitable devices may beoperably associated with the electrosurgical forceps. For example, insome instances, one or more types of springs, e.g., a compressionspring, may operably couple to the handle assembly associated with theelectrosurgical forceps. In this instance, the spring is typicallyoperatively associated with the drive assembly to facilitate actuationof a movable handle associated with the handle assembly to ensure that aspecific closure force between the jaw members is maintained within oneor more suitable working ranges.

In certain instances, the shaft may bend or deform during the course ofan electrosurgical procedure. For example, under certain circumstances,a clinician may intentionally bend or articulate the shaft to gaindesired mechanical advantage at the surgical site. Or, under certaincircumstances, the surgical environment may cause unintentional orunwanted bending or flexing of the shaft, such as, for example, in theinstance where the shaft is a component of a catheter-basedelectrosurgical forceps. More particularly, shafts associated withcatheter-based electrosurgical forceps are typically designed tofunction with relatively small jaw members, e.g., jaw members that areconfigured to pass through openings that are 3 mm or less in diameter.Accordingly, the shaft and operative components associated therewith,e.g., a drive rod, are proportioned appropriately. That is, the shaftand drive rod are relatively small.

As can be appreciated, when the shaft is bent or deformed (eitherintentionally or unintentionally) the frictional losses associated withdrive rod translating through the shaft are transferred to the spring inthe housing, which, in turn, may diminish, impede and/or preventeffective transfer of the desired closure force that is needed at thejaw members. Moreover, the frictional losses may also lessen theoperative life of the spring, which, in turn, ultimately lessens theoperative life of the electrosurgical instrument.

SUMMARY

The present disclosure provides an endoscopic forceps. The endoscopicforceps includes a housing having a shaft that extends therefrom havinga longitudinal axis defined therethrough. An end effector assemblyoperatively connects to a distal end of the shaft and includes a pair offirst and second jaw members. One or both of the first and second jawmembers is movable relative to the other jaw member from an openposition to a clamping position. One of the first and second jaw membersincludes one or more cam slots defined therein and is configured toreceive a cam member that upon movement thereof rotates the jaw membersfrom the clamping position to the open position. A resilient member isoperably coupled to one or both of the jaw members. The resilient memberis configured to bias the first and second jaw members in the clampingposition and provide a closure force on tissue disposed therebetween.

The present disclosure provides an endoscopic forceps. The endoscopicforceps includes a housing having a shaft that extends therefrom havinga longitudinal axis defined therethrough. An end effector assemblyoperatively connects to a distal end of the shaft and includes a pair offirst and second jaw members. The first and second jaw members eachhaving a respective detent operably disposed at a proximal end thereof.The first and second jaw members movable relative to one another from aclamping position wherein the first and second jaw members cooperate tograsp tissue therebetween to an open position wherein the first andsecond jaw members are disposed in spaced relation relative to oneanother. A cam assembly is movable along the longitudinal axis andincludes one or more cam slots defined therein. The one or more camslots are configured to receive the detent associated with therespective first and second jaw members. A resilient member operablycouples to the cam assembly and is configured to bias the first andsecond jaw members in the clamping position and provide a closure forceon tissue disposed therebetween.

The present disclosure provides an endoscopic forceps. The endoscopicforceps includes a housing having a shaft that extends therefrom havinga longitudinal axis defined therethrough. An end effector assemblyoperatively connects to a distal end of the shaft and includes a pair offirst and second jaw members. One or both of the first and second jawmembers is movable relative to the other jaw member that is stationaryfrom an open position to a clamping position. A support member isoperably disposed at a distal end of the shaft adjacent the endeffector. A resilient member in mechanical communication with thesupport member operably couples to the first and second jaw members. Theresilient member is configured to bias the first and second jaw membersin the clamping position and provide a closure force on tissue disposedtherebetween.

In embodiments, a plurality of non-conductive stop members is disposedon an inner facing surface of one or both of the first and second jawmembers. The stop members are configured to maintain a uniform distancebetween the first and second jaw members along the length thereof duringtissue sealing.

The present disclosure also provides a method for performing alaparoscopic surgical procedure. The method includes providing anendoscopic instrument that includes an end effector assembly including apair of first and second jaw members. One or both of the first andsecond jaw members is movable relative to the other from a clampingposition to an open position. The movable jaw member includes one ormore cam slots defined therein that is configured to receive a cammember. A resilient member is operably coupled to one or both of thefirst and second jaw members. The resilient member is configured to biasthe first and second jaw members in the clamping position and provide aclosure force on tissue disposed therebetween. A step of the methodincludes biasing the first and second jaw members in the clampingposition with the resilient member for positioning the end effectoradjacent to tissue. Moving the movable jaw member to the open positionis a step of the method. Positioning tissue between the first and secondjaw members is another step of the method. And, moving the movable jawmember to the clamping position is still yet another step of the method.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the present disclosure are described hereinbelowwith references to the drawings, wherein:

FIG. 1A is a side, perspective view of an endoscopic bipolar forcepsshowing an end effector assembly including jaw members in a closedconfiguration according to an embodiment of the present disclosure;

FIG. 1B is a side, perspective view of the endoscopic bipolar forcepsdepicted in FIG. 1A illustrating internal components of a handleassembly associated with the endoscopic bipolar forceps;

FIG. 2 is a schematic view of the jaw members depicted in FIGS. 1A and1B operably coupled to a jaw housing associated with each of the jawmembers;

FIGS. 3A and 3B are schematic views of jaw members operably coupled to adistal end of the endoscopic forceps depicted in FIGS. 1A and 1Baccording to another embodiment of the present disclosure;

FIGS. 4A and 4B are schematic views of jaw members operably coupled to adistal end of the endoscopic forceps depicted in FIGS. 1A and 1Baccording to yet another embodiment of the present disclosure; and

FIG. 5 is a side, perspective view of an endoscopic bipolar forcepsshowing an end effector assembly including jaw members in an openconfiguration according to still another embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Detailed embodiments of the present disclosure are disclosed herein;however, the disclosed embodiments are merely examples of thedisclosure, which may be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present disclosure in virtually any appropriately detailedstructure.

With reference to FIGS. 1A and 1B, an illustrative embodiment of anelectrosurgical apparatus, e.g., a bipolar forceps 10 (forceps 10) isshown. Forceps 10 is operatively and selectively coupled to a suitablepower source, such as, for example, an electrosurgical generator (notshown) for performing an electrosurgical procedure. As noted above, anelectrosurgical procedure may include sealing, cutting, cauterizingcoagulating, desiccating, and fulgurating tissue all of which may employRF energy. The generator may be configured for monopolar and/or bipolarmodes of operation. The generator may include or is in operativecommunication with a system (not shown) that may include one or moreprocessors in operative communication with one or more control modulesthat are executable on the processor. The control module (not explicitlyshown) may be configured to instruct one or more modules to transmitelectrosurgical energy, which may be in the form of a wave orsignal/pulse, via one or more cables (e.g., a cable 23) to the forceps10.

Forceps 10 is shown configured for use with various electrosurgicalprocedures and generally includes a housing 20, electrosurgical cable 23that connects the forceps 10 to a source of electrosurgical energy(e.g., the electrosurgical generator), a handle assembly 30, a rotatingassembly 80, a trigger assembly 70, a drive assembly 130 (see FIG. 1B),and an end effector assembly 100 that operatively connects to a driveelement 150 of the drive assembly 130. End effector assembly 100includes opposing jaw members 110 and 120 (FIGS. 1A and 1B) thatmutually cooperate to grasp, seal and, in some cases, divide largetubular vessels and large vascular tissues. The drive assembly 130 is inoperative communication with handle assembly 30 for imparting movementof one or both of a pair of jaw members 110, 120 of end effectorassembly 100. Conventional drive assemblies typically utilize one ormore types of springs, e.g., a compression spring, to facilitate closingthe jaw members 110 and 120. For illustrative purposes, a compressionspring 131 (see FIG. 1B) is shown separated from the housing 20.

With continued reference to FIGS. 1A and 1B, forceps 10 includes a shaft12 that has a distal end 14 configured to mechanically engage the endeffector assembly 100 and a proximal end 16 that mechanically engagesthe housing 20. In the drawings and in the descriptions that follow, theterm “proximal,” as is traditional, will refer to the end of the forceps10 which is closer to the user, while the term “distal” will refer tothe end that is farther from the user.

Handle assembly 30 includes a fixed handle 50 and a movable handle 40.Fixed handle 50 is integrally associated with housing 20 and handle 40is movable relative to fixed handle 50. Movable handle 40 of handleassembly 30 is ultimately connected to the drive assembly 130, whichtogether mechanically cooperate to impart movement of one or both of thejaw members 110 and 120 to move from a clamping or closed position (FIG.1A), wherein the jaw members 110 and 120 cooperate to grasp tissuetherebetween, to an open position (FIG. 1B), wherein the jaw members 110and 120 are disposed in spaced relation relative to one another.

Jaw members 110, 120 are operatively and pivotably coupled to each otherand located adjacent the distal end 14 of shaft 12. Respectiveelectrically conductive seal plates 118 and 128 are operably supportedon and secured to respective jaw housings 117 and 127 of respective thejaw members 110 and 120, described in greater detail below. For thepurposes herein, jaw members 110 and 120 include jaw housings 117 and127 that are configured to support sealing plates 118 and 128,respectively.

For a more detailed description of the forceps 10 including handleassembly 30 including movable handle 40, rotating assembly 80, triggerassembly 70, drive assembly 130, jaw members 110 and 120 (includingcoupling methods utilized to pivotably couple the jaw members 110 and120 to each other) and electrosurgical cable 23 (including line-feedconfigurations and/or connections), reference is made to commonly ownedU.S. Patent Publication No. 2007/0173814 (now U.S. Pat. No. 7,766,910)filed on Nov. 9, 2006.

Turning now to FIG. 2, one embodiment of jaw housings 117 and 127 isshown. It should be noted that in accordance with the present disclosureone or both of the jaw housings 117 and 127 may include a proximal endthat is configured to support one or more cam slots 202 and resilientmembers 204 to facilitate closing in of the jaw members 110 and 120. Jawmembers 110 and 120 are substantially identical to each other, and, inview thereof, and so as not to obscure the present disclosure withredundant information, the operative components associated with the jawhousing 117 are described in further detail with respect to jaw member110, and only those features distinct to jaw member 120 and jaw housing127 will be described hereinafter.

With continued reference to FIG. 2, jaw member 110, jaw housing 117, andoperative components associated therewith may be formed from anysuitable material, including but not limited to metal, metal alloys,plastic, plastic composites, etc. In the embodiment illustrated in FIG.2, jaw member 110 is formed from metal.

A distal end 117 a of the jaw housing 117 of jaw member 110 isconfigured to securely engage the electrically conductive seal plate118. A portion of a proximal end 117 b of the jaw member 110 is operablysecured to the distal end 14 of the shaft 12. More particularly, aportion of proximal end 117 b operably couples to the distal end 14 andis in operative communication with the drive element 150 of the driveassembly 130 such that movement of the drive element 150 causes one orboth of the jaw members 110 and 120 to move from the closed or clampingposition to the open position and vice versa. For example, in oneparticular embodiment, when the drive element 150 is “pulled,” i.e.,moved or translated proximally, one or both of the jaw members 110 and120 is/are caused to move away from the other. Alternatively, and ifdesired, the drive assembly 130 including the drive element 150 may beconfigured such that when the drive element 150 is “pushed,” i.e., movedor translated distally, one or both of the jaw members 110 and 120 arecaused to move away from each other. In certain instances, it may proveuseful to have a drive element 150 that is flexible. More particularly,where the drive element 150 is operatively associated with anendoluminal instrument the drive element 150 may be substantiallyflexible to accommodate bends typically associated with that type ofinstrument when the bipolar forceps 10 is remotely actuatable relativeto the patient.

In the illustrated embodiment, proximal end 117 b of the jaw housing 110includes a generally elongated configuration that may be rectangular,circumferential or combination thereof in shape.

Proximal end 117 b of the jaw member 110 includes one or more cam slots202 defined therein that support one or more cam members 205 (see FIG.2). More particularly, cam slot 202 is of suitable proportion andconfigured to receive cam member 205 and is operably formed and/orpositioned at the proximal end 117 b of the jaw housing 117. Cam slot202 includes a generally oblique configuration with respect to alongitudinal axis “B-B” that is parallel to a longitudinal axis “A-A”defined through the shaft 12, see FIGS. 1A and 2. Cam slot 202 mayextend at an angle that ranges from about 5° to about 30° with respectto the longitudinal axis “B-B.” In the embodiment illustrated FIG. 2,cam slot 202 extends at an angle that is approximately equal to 45° withrespect to the longitudinal axis “B-B.” The angle of the cam slot 202may be selectively varied depending upon a particular instrument, use ormanufacturing preference.

An opening 208 is defined in and extends through the jaw housing 117 band is configured to receive a spring pin 211. Opening 208 is shownengaged with spring pin 211 and as such is not explicitly visible. Inthe embodiment illustrated in FIG. 2, a portion of the spring pin 211 isdimensioned to securely engage the resilient member 204.

One or more types of resilient members 204 may be operably associatedwith the housing 117 and includes, for example, a torsion spring that isutilized to generate a closure force on the jaw members 110 and 120 whenthe jaw members 110 and 120 are in a closed or clamped position. Theresilient member 204 cooperates with the drive assembly 130 to providethe necessary closure force on the jaw members 110 and 120 for sealingtissue, e.g., in the range of about 3 kg/cm² to about 16 kg/cm².

Resilient member 204 operably engages jaw housings 117 and 127 and isbiased in a closed orientation. More particularly, a proximal end 212 ofsuitable proportion and having a generally circumferential configurationis dimensioned to securely couple to the spring pin 211. Two generallyelongated fingers 214 and 216 extend from proximal end 212 adjacent theproximal ends of the jaw members, e.g., proximal end 117 b of jaw member110 and a proximal end (not explicitly shown) of the jaw member 120, andfixedly couple to a respective distal end of the jaw member, e.g.,distal end 117 a of jaw member 117 and a distal end 127 a of the jawmember 120. In the embodiment illustrated in FIG. 2, the resilientmember 204 biases the jaw members 110 and 120 toward each other to aclosed position such that a consistent uniform seal is effected totissue. More particularly, the configuration of the resilient member 204is designed such that each the elongated fingers 214 and 216 areoperably disposed adjacent a respective imaginary center-line “CL” thatextends through each of the jaw members 110 and 120, see FIG. 2. In thisinstance, the force from each of the elongated fingers 214 and 216 isevenly distributed to and throughout a respective jaw member.

One or more types of lubricious materials (not shown), e.g., PTFE, maycoat cam slot 202 or an inner peripheral surface thereof. Coating thecam slot 202 with the lubricious material facilitates movement of thecam member 205 within the cam slot 202 when the drive element 150 istranslated proximally (or distally depending on a particularconfiguration).

In an assembled configuration each of the jaw members 110 and 120 arepositioned in side-by-side relation. Cam member 205 is operably disposedwithin cam slot 202 associated with jaw member 110 and a correspondingcam slot (not explicitly shown) associated with jaw member 120. Springpin 211 is positioned within the opening associated with jaw member 110and a corresponding opening (not explicitly shown) associated with jawmember 120. As noted above, the spring pin 211 provides a point of pivotfor each of the jaw members 110 and 120. Once assembled, the jaw members110 and 120 may be pivotably supported at the distal end 14 of the shaft12 by known methods, such as, for example, by the method described incommonly-owned U.S. Patent Publication No. 2007/0260242 filed on Jul.11, 2007.

In use, initially jaw members 110 and 120 are biased in a closedposition under the closure and/or sealing force provided by theresilient member 204. Proximal movement of movable handle 40 causes thedrive element 150 to move proximally. Proximal movement of the driveelement 150 causes cam member 205 positioned within the cam slot 202 tomove proximally against the bias of the resilient member 204, which, inturn, causes both of the jaw members 110 and 120 to move relative to oneanother, such that tissue is positioned between the jaw members 110 and120. Once tissue is positioned between the jaw members 110 and 120 themovable handle 40 is released, which, in turn, causes the jaw members110 and 120 to move toward one another under the biasing force of theresilient member 204 which generates a sealing or closure force on thetissue disposed between the jaw members 110 and 120. The resilientmember 204 provides an additional mechanical advantage at the jawmembers 110 and 120 and reduces the frictional losses that are typicallyassociated with conventional forceps when a drive rod is translatedwithin a shaft to make the necessary closure force to seal tissue, e.g.,the closure force is offloaded and/or diminished by the resilient member204.

With reference to FIGS. 3A and 3B, another embodiment of an end effector300 that is configured for use with the forceps 10 is illustrated. Endeffector 300 is substantially identical to end effector 100, and, inview thereof, and so as not to obscure the present disclosure withredundant information, and only those features distinct to end effector300 will be described hereinafter.

End effector 300 includes jaw members 310 and 320. As described abovewith respect to jaw members 110 and 120, jaw members 310 and 320 arepivotably coupled to each other via a spring pin or pivot pin 311. Moreparticularly, pivot pin 311 operably couples the jaw members 310 and 320about a medial portion of a respective jaw housing 317 and 327 (FIG.3A). Pivot pin 311 maintains the jaw members 310 and 320 in asubstantially fixed position with respect to the longitudinal axis “A-A”when the jaw members 310 and 320 are pivoting or rotating about thepivot pin 311. That is, the jaw members 310 and 320 do not translatealong the longitudinal axis “A-A” when movable handle 40 is moved.

A respective detent 313 and 323 is operably disposed at a respectiveproximal end 317 b and 327 b of the jaw members 310 and 320,respectively. In the embodiment illustrated in FIGS. 3A and 3B, thedetents 313 and 323 are configured to rotate the respective jaw members310 and 320 from an open position (FIG. 3A) to a closed or clampingposition (FIG. 3B) when the movable handle 40 is moved proximally.Detents 313 and 323 are proportioned to movably couple to a cam assembly330.

Cam assembly 330 translates or moves along the longitudinal axis “A-A”when the movable handle 40 is moved proximally and/or distally. To thisend, cam assembly 330 is suitably shaped and proportioned to movablyreside within the shaft 12 adjacent the distal end 14. For illustrativepurposes, cam assembly 330 is shown elongated with a generallyrectangular shape. One or more cam slots 332 are operably disposed on ordefined in the cam assembly 330. In the embodiment illustrated in FIGS.3A and 3B, two intersecting cam slots 332 a and 332 b are defined in thecam assembly 330. The cam slots 332 a and 332 b are proportioned toreceive a respective detent 313 and 323 such that the detents 313 and323 are movable along a length of the respective cam slots 332 a and 332b.

Each of the cam slots 332 a and 332 b includes a respective distal end334 and 336. The distal ends 334 and 336 are configured to function aslatches. More particularly, the distal ends 334 and 336 maintain therespective detents 313 and 323 in a substantially fixed position afterthe movable handle 40 is moved a predetermined distance proximally andthe jaw members 310 and 320 are in the clamping position.

One or more suitable unlatching devices or configurations may beutilized to unlatch the detents 313 and 323 from the respective distalends 334 and 336. For example, and in one particular embodiment, one ormore detents 335 may be operably disposed along an internal surface ofthe shaft 12. In this instance, the detent 335 may be configured tocontact a portion, e.g., a bottom surface 331, of the cam assembly 330when the movable handle 40 is moved through an “unlatching” stroke, seeFIGS. 3A and 3B. Accordingly, when movable handle 40 is moved throughthe “unlatching” stroke, the detent 335 contacts the bottom surface 331of the cam assembly 330, which, in turn, unlatches the detents 313 and323 from the respective distal ends 334 and 336. Other latching andunlatching devices and/or configurations may be utilized to latch andunlatch the detents 313 and 323 from the respective distal ends 334 and336.

One or more types of resilient members 304 operably couple to the driveelement 150 and to the cam assembly 330. Resilient member 304 may be anysuitable resilient member, e.g., a compression spring. A distal end ofthe drive element 150 operably couples to a proximal end of theresilient member 304 and proximal end of the cam assembly 330 operablycouples to a distal end of the resilient member 304. The resilientmember 304 operably couples to the distal end of the drive element 150and proximal end of the cam assembly 330 via any suitable couplingmethods. As described above with resilient member 204, resilient member304 cooperates with the drive assembly 130 to provide the necessaryclosure force on the jaw members 310 and 320 for sealing tissue, e.g.,in the range of about 3 kg/cm² to about 16 kg/cm².

In use, initially jaw members 310 and 320 are biased in an open position(FIG. 3A). Tissue is positioned between the jaw members 310 and 320.Thereafter, the movable handle 40 is moved proximally causing the driveelement 150 to move proximally. Proximal movement of the drive element150 moves the resilient member 304 proximally, which, in turn, moves thecam assembly 330 proximally. Proximal movement of the cam assembly 330causes the detents 313 and 323 to move within the respective cam slots332 a and 332 b and to the respective distal ends 334 and 336 until thedetents 313 and 323 are latched into a closed or clamping position (FIG.3B). In the latched position, the requisite sealing or closure force ispresent on the tissue disposed between the jaw members 310 and 320.Thereafter, electrosurgical energy is transmitted to seal surfaces 318and 328 operably associated with respective jaw members 310 and 320 suchthat a desired tissue effect, e.g., a tissues seal, may be achieved onthe tissue disposed between the jaw members 310 and 320. To open the jawmembers 310 and 320, the moveable handle 40 is moved through an“unlatching” stroke that unlatches or releases the detents 313 and 323from the respective distal ends 334 and 336 such that the jaw members310 and 320 return to the initial open position.

With reference to FIGS. 4A and 4B, an end effector 400 that isconfigured for use with the forceps 10 is illustrated. End effector 400is substantially identical to end effectors 100 and 300, and, in viewthereof, and so as not to obscure the present disclosure with redundantinformation, only those features distinct to end effector 400 will bedescribed hereinafter.

End effector 400 includes jaw members 410 and 420. In the embodimentillustrated in FIGS. 4A and 4B, one of the jaw members, e.g., jawmembers 420, is movable, and one of the jaw members, e.g., jaw member410, is stationary. This configuration of jaw members 420 and 410 may bereversed to accommodate various surgical procedures. Jaw members 410 and420 are pivotably coupled to one another via a pivot pin 411.

A support structure or member 430 is operably disposed along an internalframe of the shaft 12 adjacent the distal end 14. More particularly, thesupport structure 430 is operably coupled to a top portion of theinternal frame of the shaft 12. Support structure 430 is configured tomechanically communicate with a resilient member 404. More particularly,the support structure 430 provides a substantially rigid surface that isconfigured to compress the resilient member 404 when the resilientmember 404 is moved proximally and the movable jaw member 420 is movedto the open position. To this end, support structure 430 may have anysuitable shape. In the embodiment illustrated in FIGS. 4A and 4B,support structure 430 includes a generally circumferential configurationhaving an aperture 406 of suitable proportion defined therethrough.Aperture 406 is includes a diameter that is sized to receive the driveelement 150 (or portion thereof) that includes a distal end thatoperably couples to a proximal end 427 b of the movable jaw member 420.More particularly, the diameter of the aperture 406 is such that thedrive element 150 is movable through the aperture 406 when the movablehandle 40 is moved proximally and/or distally. Additionally, theaperture 406 is proportioned such that the resilient member 404 isprevented from translating therethrough when the movable handle 40 ismoved proximally and/or distally.

In the embodiment illustrated in FIGS. 4A and 4B, the support structure430 is configured to maintain the drive element 150 in a substantiallyfixed off-set orientation above the pivot pin 411, see FIG. 4A, forexample. Having the support structure 430 configured in such a mannerfacilitates moving the jaw member 420 about the pivot pin 411.

Resilient member 404 is operably disposed between the support structure430 and the proximal end 427 b of the jaw housing 427. In anuncompressed state, resilient member 404 cooperates with the supportstructure 430 to provide the necessary closure force on the jaw members410 and 420 for sealing tissue, e.g., in the range of about 3 kg/cm² toabout 16 kg/cm². To this end, the resilient member 404 may be anysuitable resilient spring, e.g., a compression spring 404, including,but not limited to those previously described herein. The compressionspring 404 is proportioned such that the drive element 150 ispositionable therethrough, FIG. 4A.

In use, initially jaw members 410 and 420 are biased in a closedposition under the closure and/or sealing force provided by thecompression spring 404 (FIG. 4B). Proximal movement of movable handle 40causes the drive element 150 to move proximally. Proximal movement ofthe drive element 150 causes the moveable jaw member, e.g., jaw member420, to move relative to the stationary jaw member, e.g., jaw member410, such that tissue is positioned between the jaw members 410 and 420.Once tissue is positioned between the jaw members 410 and 420 themovable handle 40 is released, which, in turn, causes the jaw member 420to move toward jaw member 410 under the biasing force of the compressionspring 404 which generates a sealing or closure force on the tissuedisposed between the jaw members 410 and 420. The compression spring 404provides an additional mechanical advantage at the jaw members 410 and420 and reduces the frictional losses that are typically associated withconventional forceps when a drive rod is translated within a shaft tomake the necessary closure force to seal tissue, e.g., the closure forceis offloaded and/or diminished by the compression spring 404.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, other resilient members, e.g., leaf springs,compressed gas, resilient bladder, spring washers and bellows, may beoperably associated with any of the aforementioned configurations ofutilized to generate a closure or sealing force at the jaw members.Moreover, the resilient members 204, 304 and 404 may work in combinationwith one or more springs located with the shaft 12 or housing 20 thatare operatively associated with the drive assembly 130 to generate thenecessary forces associated with tissue sealing.

As best seen in FIG. 5, in order to achieve a desired spacing betweenthe electrically conductive surfaces of the respective jaw members,e.g., jaw members 110 and 120, (i.e., gap distance) and apply a desiredforce to seal the tissue, one or both of the jaw member 110 and/or 120may include one or more stop members 350 that limit the movement of thetwo opposing jaw members 110 and 120 relative to one another. The stopmember 350 may be disposed on an inner facing surface of one or both ofthe jaw members 110 and 120. More particularly, stop member 350 extendsfrom a seal surface 118 a of seal plate 118 a predetermined distanceaccording to the specific material properties (e.g., compressivestrength, thermal expansion, etc.) to yield a consistent and accurategap distance during sealing. In the illustrated embodiment, the stopmembers 350 extend from the seal surfaces 118 a and 128 a a distancethat ranges from about 0.001 inches to about 0.006 inches. The gapdistance between opposing sealing surfaces 118 a and 128 a duringsealing may range from about 0.001 inches to about 0.006 inches and,preferably, between about 0.002 and about 0.003 inches. Theconfiguration of a seal surface 118 a with stop members 350 facilitatesin maintaining a uniform distance between the jaw members 110 and 120along the length thereof during tissue sealing.

For a more detailed description of the stop members 350 and operativecomponents associated therewith, reference is made to commonly-ownedU.S. patent application Ser. No. 12/348,748 (now U.S. Pat. No.8,241,284) filed Jan. 5, 2009.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

1-7. (canceled)
 8. An endoscopic forceps, comprising: a housing having ashaft that extends therefrom defining a longitudinal axis therethrough;an end effector assembly operatively connected to a distal end of theshaft and including a pair of first and second jaw members, the firstand second jaw members each having a respective detent operably disposedat a proximal end thereof, the first and second jaw members movablerelative to one another from a clamping position wherein the first andsecond jaw members cooperate to grasp tissue therebetween to an openposition wherein the first and second jaw members are disposed in spacedrelation relative to one another; a cam assembly movable along thelongitudinal axis and including at least two cam slots defined therein,the at least two cam slots configured to receive the detents associatedwith the respective first and second jaw members; and a resilient memberoperably coupled to the cam assembly and configured to bias the firstand second jaw members in the clamping position and provide a closureforce on tissue disposed therebetween.
 9. An endoscopic forcepsaccording to claim 8, wherein the resilient member is operably coupledto a drive rod of a drive assembly that, in turn, is operably associatedwith the endoscopic forceps, wherein movement of the drive rod in theproximal direction moves the first and second jaw members from the openposition to the clamping position.
 10. An endoscopic forceps accordingto claim 8, wherein the at least two cam slots are disposed in agenerally oblique orientation with respect to each other.
 11. Anendoscopic forceps according to claim 8, wherein the resilient member isoperably coupled to a proximal end of the cam assembly.
 12. Anendoscopic forceps according to claim 8, wherein the resilient memberprovides a closure force of about 3 kg/cm² to about 16 kg/cm².
 13. Anendoscopic forceps according to claim 8, further including a pluralityof non-conductive stop members disposed on an inner facing surface of atleast one of the first and second jaw members, the plurality ofnon-conductive stop members being configured to maintain a uniformdistance between the first and second jaw members along the lengththereof.
 14. An endoscopic forceps according to claim 13, wherein theplurality of non-conductive stop members extend from the inner facingsurface a distance that ranges from about 0.001 inches to about 0.006inches.
 15. An endoscopic forceps, comprising: a housing having a shaftthat extends therefrom defining a longitudinal axis therethrough; an endeffector assembly operatively connected to a distal end of the shaft andincluding a pair of first and second jaw members, at least one of thefirst and second jaw members movable relative to the other from aclamping position wherein the first and second jaw members cooperate tograsp tissue therebetween to an open position wherein the first andsecond jaw members are disposed in spaced relation relative to oneanother; a support member operably disposed at a distal end of the shaftadjacent the end effector; and a resilient member in mechanicalcommunication with the support member and operably coupled to the firstand second jaw members, the resilient member configured to bias thefirst and second jaw members in the clamping position and provide aclosure force on tissue disposed therebetween.
 16. An endoscopic forcepsaccording to claim 15, wherein the support member includes a generallycircumferential configuration with an aperture extending therethrough,the support member providing a substantially rigid surface that isconfigured to compress the resilient member when the resilient member ismoved proximally and the movable one of the first and second jaw membersis moved to the open position.
 17. An endoscopic forceps according toclaim 15, wherein the aperture is configured to receive a drive rod of adrive assembly that is operably associated with the endoscopic forceps.18. An endoscopic forceps according to claim 17, wherein a distal end ofthe drive rod operably couples to the proximal end of the movable one ofthe first and second jaw members.
 19. An endoscopic forceps according toclaim 15, further including a plurality of non-conductive stop membersdisposed on an inner facing surface of at least one of the first andsecond jaw members, the plurality of non-conductive stop members beingconfigured to maintain a uniform distance between the first and secondjaw members along the length thereof.
 20. An endoscopic forcepsaccording to claim 19, wherein the plurality of non-conductive stopmembers extend from the inner facing surface a distance that ranges fromabout 0.001 inches to about 0.006 inches. 21-28. (canceled)